This invention relates generally to mass mail handling equipment. More particularly, this invention relates to an improved apparatus for taking a series of flat articles such as envelopes, orienting them, and then stacking the articles in groupings.
In the high volume mail industry, in both U.S. First Class and Third Class mail, envelopes are filled with various letter pieces using automated mail inserters. For example, U.S. Pat. Nos. 5,029,832 (Orsinger et al.) and 5,211,384 (Orsinger et al.) disclose an in-line inserter device having envelope and feeding assemblies, an envelope inserting station, a sealing and stacking assembly, and various diverter stations.
Mass-mailing equipment has become very diverse in its functions. For instance, inserting equipment transports envelopes along an inserting track while various types of inserts are automatically inserted into the envelopes. The envelopes are normally transported to another piece of equipment that automatically seals the envelopes, weighs them and affixes postage. Still additional equipment automatically reads the zip codes or zip code indicia on the envelopes and indicates zip code breaks in the envelope groups for zip code presorting. This allows the user to take advantage of lower postage rates. Other mass-mailing equipment may include remittance processing equipment and zip code sorting equipment.
These mail-inserters may run at speeds, for example, from several hundred filled envelopes per hour to approximately 14,000 envelopes per hour. These speeds have created a need on the end of the inserters to collect the filled envelopes in such a way as to allow the operator to load them into mail trays or other forms of storage quickly and efficiently. In addition, since these envelopes are often prearranged in special zip code order, this order must be maintained by the operator and then separated into different trays depending on these zip code groupings.
U.S. Pat. Nos. 6,398,204 (Keane et al.) and 6,540,223 (Keane et al.) address these issues, however, these methods have limitations as the envelopes being processed become larger. The invention of these two patents rely on sliding the incoming envelope behind the previously stacked envelope. However, this invention may create difficulties when dealing with the larger “flat” envelopes (flats being defined as envelopes that are approximately six inches by nine inches and larger). Because these envelopes tend to have more documents in them and thus be thicker, and because of the increased surface area of these envelopes, they have difficult sliding behind the previous envelope efficiently.
Currently, many mail inserters simply eject the filled envelope onto a short flat conveyor, allowing the envelopes to free float on the conveyor. This creates the possibility that the zip order of the envelopes will get mixed up, the possibility of envelopes becoming disorderly and difficult to quickly pick up, and the possibility of envelope flaps popping opened prior to proper glue drying. Additionally, this method is an inefficient use of conveyor space, allowing only a short amount of time before the conveyor becomes full. All of these limitations require increased attention from an operator. Often, an operator is forced to shut down the entire inserting machine so that he or she can catch up with the emptying of the conveyor. Obviously, this drastically reduces the overall throughput of envelopes.
These mail inserters may run at speeds, for example, from several hundred filled envelopes per hour to approximately 18,000 envelopes per hour. These speeds have created a need on the end of the inserters to collect the filled envelopes in such a way as to allow the operator to load them into mail trays or other forms of storage quickly and efficiently. In addition, since these envelopes are often prearranged in special zip code order, this order must be maintained by the operator and then separated into different trays depending on these zip code groupings.
This area has proven to be the “bottleneck” of the mail insertion process. Many times, the operator has a difficult time keeping up with the inserter. Additionally, the envelopes are not presented in such a way that the zip code breaks can be read easily. The operator may develop fatigue, possibly even carpal tunnel syndrome, because of excess handling of envelopes. One means to assist here is the inclusion of an envelope stacking apparatus at the end of the system to secure the sorted mail pieces in a stacked position to facilitate the orderly removal of the processed mail pieces from the system.
One feature of many on-edge stacking conveyors is the ability to offset the registered edge of a horizontal envelope stack so as to easily identify the zip code change or count to the offloading operator. This is typically accomplished by a printing, such as a zip code, bar code, optical mark, etc., on the envelope, read by an electronic reading device, as the envelope enters the on-edge stacking apparatus. This data is then used to index an offsetting device that causes the front perimeter edge of the envelope stack to create an offset from the envelopes previously received in the stack. That is, a series of envelopes is first stacked against a register wall. When a new zip code break is read, the offset device causes new envelopes to be offset by a small amount. The result is an indexed stack with zip code breaks easily identified. In present systems, after a set of envelopes has been offset by the offset device and a new zip code break is read, the next set of envelopes coming in no longer is required to be offset. However, the first incoming envelope of a new set may drag the prior, offset, envelope back to the register wall due to frictional drag. This occurs particularly when the offset device is withdrawn too soon. This may be overcome by delaying, for example, via software, the moment when the parallel wall of the offset device is retracted to several inches before the new envelope gets to the offset device. This solution is only partially successful because the retraction of the offset device must be started early because the front lip of the offset must be clear before the new envelope passes it. Because there are still several inches of travel for the incoming envelope, there is still some frictional drag of the prior envelope.
The present invention is directed to these limitations in past systems.
Many other attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
All references cited herein are incorporated herein by reference in their entireties.